At the boundary between the European and Adria plates, the Northern Apennine represents a polyorogenic belt, resulted from the Oligocene-Pliocene eastward progressive overthrusting of the Ligurides on the detached sedimentary cover of the Adria plate continental margin (Foredeep Units). The Ligurides, deriving from the Ligurian-Piedmont ocean and its transition to the Adria continental margin, were deformed during Eo and Mesoalpine Phases; as a result, they should be considered as a structural element of the Alpine belt, included in the Apennine orogenic prism since the Oligocene. In this context, the Alps-Apennine boundary corresponds to the overthrusting at the base of the Ligurian nappes. Considering the northwestward axial plunging, the Northern Apennine structure can be defined by moving from SE toward NW, and subdivided into two main longitudinal tectonic domains: the Western Domain (Ligurian-Tyrrhenian) and the Eastern Domain (Po-Adriatic), each showing a complete structural stacking. At the boundary between these two domains, the tectonic relations between Macigno and Modino foredeep units are interpreted as due to a W-verging thrust, splay of a flower structure developed in a transpressive fault zone active after the Aquitanian. The dextral strike-slip movements along this tectonic element would have produced the duplication of the Ligurian and Subligurian structural stacking, and could better explain the Alpine-derived coarse-grained and proximal deposits occurring in the thrust-top basin deposits of the Epiligurian Succession and in the Aveto-Petrignacola Fm (Subligurian domain). The transcurrence all along the junction of the two tectonic domains is contemporary to the development of the duplex structure in the Eastern Domain. Thus, the overall structure of the Northern Apennine can be interpreted as derived from a transpressive tectonics.